After 5 and a half months we have finally managed to modify the in-activity timeout of Arena. It seems the ASP Session State timeout is not the only thing that needs to be changed. Lets not even talk about the fact you can change it in 4 different places, each having it’s own distinct value. We also had to update the forms authentication timeout (thanks Nick!) value. Now both are set to 60 minutes and our people are much happier not having to log in after a phone call.